Brake mechanism.



c. WNE, c. 0. HENDRY & J. B. KIRKALDIE.

I BRAKE MECHANISM.

APPLICATION FILED APR. I1. 1911.

r, y 25, i

CHQRLE6 D. HENDRY James B. KIRKHLDIE alto Lam:

Patented Aug.v 28, 1917.

UNITED STATES PATENT OFFICE Q; 9 J1 CHARLES A. LANE, CHARLES D.

HENDRY, 7 AND JAMES B. VKIBKAL WASHINGTON.

BRAKE MECHANISM.

State of Washington, have invented certain new and useful Improvements in Brake Mechanisms, of which the following is a specification, reference being had to the accompany'ing drawings.

This invention relates vehicle brake of the internal type wherein the brake shoesfarelocated-with the drum fixed'to the vehicle wheel and are outwardlyextended to exerts braking frictional pressure against" tfesurface of the 'dru m wall. It is the p1" ary object of our invention to provide a brake mechanism as above char-- may be expanded to exert a braking pressure acterize'dywhichis so constructed and oper ated that the braking shoes will exert a uniform frictional pressure against the wall of thebrake f It is a more particular object of our invention to providepairs of brake shoes within the drum; the-shoes in each pair being ar ranged" in opposed relation and normally held yieldin'gl' y" agai st relative -outward movement, and operating mechanism .to coact with the respective pairs of brake shoes whereby eitherfl'one; or .tbgth pairs of shoes upon the'jdrum' Wall.

And .itis alsoone of thedetail'objects df ture or -.breakagelof the parts ofthe meeh'a nism .due' to strains consequentupon the;

torque occurring at the moment of application or release of the brake shoes-is obviated.-

With the above-and other Objects'in -vi'ew,.;.

our invention consists in thenovel features described,-claimedQandillustrated intneae,

v companying.drawings,, in which,

of construction, combinationpand arrange-' ment of parts to behereinaffter more fully Figure 1"'s an levati athe-h-Qtsringi e I being removed, illustrating the refe'rred; embodiment 'of our improved brake 'lnecha- 1 msm-'- .fl t

' Fig. 21s a section taken on the line of i 1 Fig. 1'; and

Fig. 3 is a section taken on the line ofFig. 1.

" Specification of Letters Patent.

f'outer. .face ;of the housing the end ofthe sleeve.

v In the. accompanying drawing, 5 designates the brake "drum which is'bolted or Patented Ai1g. 2 8 191'7. Application filed Apri111,1917. serial n. 161,300.;

otherwise rigidly fixed-tothe'. vehicle wheel,

said drum having an onter annular-Wall or flange 6.

is closed by a housing is suitably fixed to 't dicated'. at 9.

contignous'to the inner face ofthe side wall The inner open side of the brake drum 5.

plate-or wall 8-whicjh e. rear. axle casing in- I A. plate '10 .is' disposed inf.

spaced relation. to the housing f-wall 8 and- .65

of the drum 5. This plate 10 is rigidly con "nected to the plate 8', at diametrically oppositepoints by the transverselydisposed metal bars 11-; the purpose ofwhich willbe hereinafter fully set forth."

Each of the brake shoes consists of an an cuate-bar or plate l2', theouter face of which is concentric with the wall 6 oflth'e brake drum. The terminals of the brake shoe areenlarged, as indicated at "13, and these terminals, as well as the body of the shoe which I connects the same, are provided with the fac- .ing strips 7 of felt, leather, or other frictional};

material 'for engagement with thedrum'80 wall. Between the terminals 13 of the brake shohg said shoe is formed with an inw wardly-projecting-webl on its central por}. tion,.and this web at its centeris'provided "with an integral, inwardly projecting lug-15 having-a slot 16 therein through whichthe bar 11 extends. The end portions 13 of the brake shoe are provided on theirend faces with the concave seating surfacesl'l'; the invention to provideabrakesho'eofi nnproved construction, and-means fQr-'mount' ng the a w i the dr whe eby 1 At diametrically opposite sides of the axlecasing, bearings 18 are "secured to the 2.0 is otatably 'mounted in'each of the ;bear-' I wallS, and "at 'cQIL' ponding points, bearing platesor sup: tports19-are secured to thep flfi 0-3 v in-g's 18,"and-a shaft 21 extends thronghthis sleeve and is rotatable with respect thereto;--

said 'shafft'Ibeing'supported atiitsout'er endinthe bearing-plate19. 'Upon eaclr of the sleeves 20; a "substantially ,elliptical {shaped cam-22 is fixed,- and these cams'operatefre-j uspectively between the opposedlter'minals13" -'of-on'e pair'of the brake shoes. I Similar cam members 23 are also fixed upon each shaft iof thefother pair of brake-shoes. ,To each sleeve 20; an arm 24 is fixed, and a similar I arm 25 isT-als0 fixed to each shaft 21 beyond The two arms 24 and 4 v arms have short bars26 pivotally' con- 1 .curved seatin nected to their other ends, each of said oars having a threaded bore to receive the ends of the rods 27 which connect the pairs of arms or levers for simultaneous operation.

Any suitable actuating connections may be provided for convenient operation by the tracted and yieldingly heldagainst relative outward movement by the coil springs 28 arranged upon opposite sides of the axle and connected at their terminals to the re spective pairs of brake shoes.

In the normal condition of the brake mechanism, when the vehicle wheel has free and unretarded rotation, the earns 22 and 23 .are disposed inthe positions seen in Fig. 1,

the concave seating faces 17 of, the terminals of the brake shoes beingengaged upon the longitudinally curved side faces ofthe elliptical cam members. When it is desired to apply a braking pressure to the drum 5, one pair of the brake shoes will be Operated as, for instance, by the actuation of the lever arms 24/ When these arms are moved, the sleeves 20 rotate upon the respective shafts 21, and the cams 22 will thus be rocked or turned between the opposed ends of one pair of brake shoes to position the longer axes of saidcams obliquely with respect to the circumference of the'brake shoes as seenin dotted lines in Fig- 1. The end portions of the cam members ,thus cooperate with the faces 17 of the brake shoes to move the bralie shoes outwardly against the contractile action of the springs 28 and engage the outer faces of said shoes with the will wear evenly. Theseveral elements of the device are very compactly arranged and inner surface of the drum wall 6. At the moment of such frictional braking contact, there will be a tendency to circumferential movement of the brake shoes with respect to the drum. As thebars 11, however, remain engaged in the slots 16 of the brake shoes, when the latter are in their elfectivebraking positions, the shoes are rigidly held against such movement and liability of rupture of the parts or displacement of the springs and high frictional wear upon the seating faces 17 is thus obviated. If additional braking pressure is desired, the other cams 23 are actuated in like mannerso that the second pair of brake shoes are expanded and caused By the provision of, the cams co-acting I against the opposite ends of the opposed brake shoes, there is a uniform braking pressure applied to the drum 6 so thatthe same the interior of the drumis entirely closed by the housing wall 8 so that dust and dirt will not enter the same, We have above referred to a particular form of the cam members which hasibeen found highly effective and satisfactory in practical use, but it is apparent, of course, that these cam members may be of other forms whereby the brake shoes are effectively actuated. The construction of the drum, as well as the form, pro-. portions, and relative arrangement of the several other parts, may likewise be considerably'modified, and We, therefore, reserve the privilege of adopting all such legitimate changes aS may be fairly embodied within the spirit and scope of the invention as claimed. x

Having thus fully described our invention, what we desire to claim and secure by Letters Patent is:

1. A brake mechanism for vehicles-including in combination with a brake d'rum, two pairs of rigid brake shoesarranged within the drum, the shoes in each pair being disposed in opposed relation to each other, and

independently operable means disposed be tween the confronting end portions of the brake shoes in each pair to 'o-act therewith, whereby the shoes in either pair may be urged outwardly in relatively opposite directions to simultaneously engage all portions of their peripheral faces with the wall of the brake drum.

I 2. A brake mechanism for vehiclesinclud each sleeve to co-act with the opposed ends I of the other pair of brake shoes, means operatively connecting the sleeves to each other, and means operatively connecting the shafts to'each otherto simultaneously 013- mate the corresponding camsqand independently urge the brake shoesjof the respective pairs outwardly into braking. engagement with the drum wall. a

- In testimony whereof we hereunto affix our signaturesv in the presence of two witnesses.

CHARLES A. LANE. CHARLES D. HENDRY. J. B. KIRKALDIE.

Witnessesz JOHN AvnY, MABEL V. Avnr. 

